(1) Field of the Invention
The present invention generally relates to a dual flush fill valve assembly for a toilet, and in particular to a dual flush fill valve assembly having a means to increase the volume of water in a toilet tank between flushes.
(2) Description of the Prior Art
Toilets can be found in almost every home and office building in the developed world and commonly use a fixed and excessive amount of water per flush. Although people prefer not to waste this water, there is no pleasant alternative to using the toilet. People prefer a toilet that uses only the amount of water needed to remove waste.
With the ever-increasing population, the conservation of water has become a greater priority. Efforts from local to global organizations are encouraging people to conserve water. In an effort to conserve, people are doing everything from displacing tank water with tank inserts to installing entirely new toilet systems. However, displacing a consistent amount of water to flush two types of waste (liquid and solid) is still an inefficient use of water, and installing a new toilet system is costly and labor intensive. These factors are major deterrents to maintaining a toilet that minimizes the use of water. These problems exist in private and professional situations where toilets are used.
In an effort to save water, dual flush toilet designs have previously been introduced that provide different flush volumes depending on the type of waste. U.S. Pat. No. 6,484,327 B2 to Hand (2002) shows a common two valve strategy that allows water to exit the tank from either an upper or lower valve. Given the fixed amount of water in the tank, these valve positions dispense a low and high volume of water, respectively. While this design, and the other dual valve systems like it allow varying volumes of water to be dispensed, multiple valves provide more opportunities for water to leak past the valves. The likelihood of a continually refilling (‘Running’) toilet is three times greater than a single valve toilet since a leak could occur at each of the two valves or at the point where the upper outflow tube section is adjustably coupled to the lower outflow tube section. Additionally, the installation of such a device requires affixing and sealing the outflow tube to the bottom of the toilet tank. This cannot be done without removing the tank, making installation difficult. Finally, this design requires multiple actuation lines as a connection must be made to each of the valves.
U.S. Pat. No. 6,829,787 B1 to Pipenburg (2004) shows a dual valve system that dispenses a low volume of water if the handle is partially depressed and a large volume if the handle is fully depressed. As with the previous design, this design introduces more leak opportunities than a single valve system and requires toilet tank removal for installation. Additionally, this and similar designs require a significant amount of component changes to convert a standard gravity flow toilet to a dual flush system. As the effort to save resources applies to water and other resources (plastic), it is preferred to reduce the waste created by component differences when upgrading to a dual flush system.
U.S. Pat. No. 7,062,801 B2 to Oliver (2006) shows another common way of controlling flush volume. The flapper valve, having an air pocket to keep the valve raised and open while submerged, is connected to a means for removing the air. While this design appears to successfully offer variable flush volumes, it uses a complex air valve system that presents a greater opportunity for malfunctions due to air leaks and blockages.
All the devices heretofore known suffer from one or more of the following disadvantages:
a. Failure to be adaptable to existing toilet systems.
b. Failure to use variable amounts of water per flush based on the type of waste.
c. Failure to conserve resources by requiring only a minimal amount of component changes to convert a conventional gravity fed toilet to a dual flush toilet.
d. Failure to provide dual flush functionality without the use of electricity.
e. Failure to allow the installer to adjust the volumes of each flush mode.
f. Device is specific to only one brand of toilet.
g. Creation of additional potential leak points.
h. Inability to be installed without significant effort such as removing the toilet tank.
i. Device requires modification or replacement of the existing flapper valve or flapper valve actuation system (flush lever).
j. Device fails to remove water from the bottom of the tank on every flush allowing the buildup of contaminants on the bottom of the tank.